Technical Instructions
LMV Series
Document No. LV5‐1000
The purpose of the standardization (calibration) procedure is to establish the relationship between the
LMV52 analog output signal (4‐20mA) and the blower speed, as read by the speed sensor connected to
the LMV52. This is done by recording a blower speed with 19.5 mA applied to the VFD. Once started,
basic steps in the standardization are as follows:
1. The air damper is opened to pre‐purge position.
2. The run / stop dry contact in the LMV52 is closed.
3. An analog signal of 19.5 mA is applied to the VFD.
4. The VFD / blower ramp up to speed. After the speed has stabilized, the actual peak RPM is recorded
by the LMV52.
5. The analog signal is returned to minimum (typically 4 mA).
6. The run / stop dry contact in the LMV52 is opened.
7. The air damper is returned to home position.
A typical standardization process for a 2‐pole (~3600 RPM) blower is shown graphically in Figure 5‐3. If a
standardization was performed on a 4‐pole (~1800 RPM) blower, the procedure would be similar but the
blower speed achieved at 19.5 mA would be approximately 1750 RPM.
Section 5
Page 10 SCC Inc.
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